A power supply apparatus may include: first and second power supplies; and a converter having first to fourth switching elements, first to fourth diodes, and first and second reactors and connected to the first power supply, the second power supply, and a load and that boosts power from the first and second power supplies and supplies the power to the load by controlling the first to fourth switching elements (see Japanese Patent Application Publication No. 2012-070514, for example). This power supply apparatus generates control signals for the first to fourth switching elements based on a logical operation of a first control pulse signal for controlling output of the first power supply and a second control pulse signal for controlling output of the second power supply, and uses these control signals to execute switching control of the first to fourth switching elements. At this time, it is adapted such that rise timing of the first control pulse signal overlaps rise timing of the second control pulse signal.
The above-described power supply apparatus is required to sequentially perform the logical operation by an arithmetic unit or to be provided with a logic circuit between the arithmetic unit and the first to fourth switching elements in order to generate the control signals for the first to fourth switching elements from the first and second control pulse signals. Such a problem arises that a processing load of the arithmetic unit becomes relatively large in the former case and the number of components of the power supply apparatus becomes relatively large in the latter case.